Base for incandescent lamps.



No. 775,689. PATENTED NOV. 22, 1904.

A. SWAN.

BASE FOR INGANDESCENT LAMPS.

- APPLIGATION FILED MAR. 27, 1903.

NO MODEL.

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No. 7%,eee.

NITED Smarts Patented November 22, race.

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ALFRED SWAN, OF NEW YORK, N. Y, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPURATION OF NEW YORK.

ease Foe iaioanneeoerl'r LAMPS= SPECIFICATION forming part of Letters Patent No 775,689, dated November 22, 1904. Application filed March 27, 1903. Serial No. 149,828. No model.)

1'0 all whom it may concern.-

Be it-known that I, ALFRED SWAN, a subject of the King of Great Britain, residing in the city, county, and State of New York,'have invented certain new and useful Improvements in Bases for Incandescent Lamps, of which the following is a specification.

- This invention relates to a base for an incandescent lamp by which the lamp is held in a suit-able socket and electrical connection made between the lamp-terminals and the terminals' of a working circuit.

In the common type of incandescent lamps the lamp-bulb is blown from a glass tube the diameter of which approximates the diameter of the metallic shell which forms one terminal of the lamp. The neck of the bulb fits into the shell of the base and is held by a suitable cement, the small surface of the neck of the bulb td which the cement adheres being quite sufficient to insure a firm joint on account of the small size and light weight of a bulb of that type. It has been found desirable, however, to make bulbs much larger than those now in general use, and for this purpose a glass tube of greater diameter must be used from which to form the bulb. Such a bulb therefore could not be sealed in the common typeof base, as the neck is the same size as the original glass tube. This neck could of course be contracted to the size of the shell;

7 but in that case a joint between the bulb and shell would not be of suflicient strength to form a good support for the bulb, and, besides, it would add expense to the product. The size and shape of the larger bulb require that a greater portion of the glass surface of the bulb be held by the cement, and a bulb-holder of larger diameter than the ordinary shell is therefore necessary, At the end opposite that in which the bulb-stem is mounted thisyholder must be rigidly secured to terminals by which the lamp may be inserted in the sockets now in general use to connect it in circuit. As the bulb-holder extends out beyond a socket,

it is important that it should be insulated from the parts which carry the current, for otherwise a person mlght receive a severe shock while inserting a lamp in a socket or removing it therefrom. Theliability to receive a shock would be increased in some types of lamps in which a metallic reflector is used fitting closely around the holder and resting on the upper portion of the bulb. It would be difficult to handle such a lamp without touching the reflector, which would of course complete a circuit to the holder.

In view of the above-enumerated requirements I have provided a cylindrical metallic bulb-holder partially closed at one end and slightly larger in diameter than the glass tube from which the bulb is blown, and 1 find that the exterior surface of that portion of the neck which fits into the holder, owing to its increased diameter, affords a surface for the adhesion of the cement suificiently large to insure a rigid and, strong joint between the bulb and holder, that the necessity for altering the size of the neckafter the bulb is blown secure to but insulate from the partially-closed end of the holder the parts which form the lamp-terminals and which hold the lamp in the socket, so that the completed base comprises three metallic parts rigidly secured together, but insulated one from another. Two of these parts form the circuit-terminals and are made in any of the forms that havegone into general usage to permit using the lamps in existing sockets. The third part forms the bulb-holder and is expanded so as to receive a bulb-neck larger than the neck of the ordinary incandescent lamp. To insulate the metallic 'parts from one another, I prefer to use a filling of glass, which not only is an excellent insulator, but when reduced to a fluid state can be run in between the parts and mold ed into the desired form.

The features of novelty embodied in my in scription, which will be the better understood sealed joint.

adheres.

by refercnceto the accompanying drawings, in which I have illustrated the larnp-base as equipped with the Edison type of terminals, though it is to be distinctly understood that Thomson-Houston, Westinghouse, or any other terminals may be used instead.

lo the drawings, Figure 1 represents an elevation of an incandescent lamp provided with my improved base, the bulb and shade being broken away and sectioned, in part, to better illustrate the construction. Fig. 2 is a sec tionalview of the completedbase. Fig. 3 is a top view of the bulb-holder before being united to the other parts, and a is an elevation of the three metallic parts of the base.

in Fig. l, l is a lamp-bulb blown from a glass tube which is larger in diameter than the threaded shell of base used with standard constant-potenti sockets. The stem .2, carrying the filament 3, i in the ordinary manner. T is a cylindrical shell ps i and of a diameter sligh" tube from which one end than the the suitable cement. The holds" vided with a groove 16 on its inner side near the open end to increase the strength of the Around holder and over a portion of the bulb is the reflector 5, its con--v tact with the holder necessitating insulation of the letter from the lamp-terminals.

The construction of the base is best shown in Fig. 2. The inner edge of the partiallyclosed end 6 of the holder 4 is provided with upwardly-extending flanges i, which are embedded in the glass 9 and to which the glass These flanges be punched to form tangs 8 to give additional strength to the joint between the glass and the holder. gecured' to the holders, but insulated therefrom by the glass 9, is the threaded shell 10, held in place by the adhesion of the glass to its inner surface. This shell is preferably formed with a dome-shaped bottom, as indicated at 11 and as described in my applica tion, Serial No. 53,882, filed April 1, 1901, to

reduce the waste of material and turned under slightly to form a flange which interlocks with and is embedded in the glass. The center contact is preferably a thin circular metallic piece 12, provided with a hollow stem 13. This is also secured to but insulated from the shell 10 and holder 4 by the filling of glass, and the end of the stem 13 is flared over, as shown in Fig. 2, by the plunger which molds the glass, so as to form an interlocking joint with the glass.

The use of glass asan insulator is a distinct advantage, as it may be run in around themetallic parts in afiuid state while they are held in the proper relative position in a suitablyshaped mold and then pressed into the form shown in Fig. 2 by-a plunger. in cooling the glass adheres to the metallic parts, form ing a firm bond between theparts and making the base practically moisture-proof and airtight. I 1

The closed-in portion 6 of cut away between two of the flanges 7, as indicated at 14: in Figs. 3 andl, so that one of the leading-in wires of the lamp may be drawn through this opening andsoldered to the shell. A button of glass is formed around the edge of this opening, as'indicated at 15, to prevent electrical connection to the holder. The other leading-in wire is drawn through the hollow stem 13 of the center contact 12 and soldered thereto. The holes in which the leading-in wiresaresoldered are filled -with solder, making the base moistu re-proof.

What I claim. as new, desire to secure by Letters Patent ot' the United States, is-

1 A base for an incandescent lamp, comprising metallic contacts to which the lampwires are attached, and a metallic bulb-holder secured to but nsulated from the contacts by glass, said bulb-holder having a flange formed thereon which is embedded in they glass.

2. base for an incandescent lamp, cornising a threaded-shell contact, a center conct, and a bulb-holder, securedto but insupr t a flange formed thereon which is embedded in the insulation.

3. A base for an incandescent lamp, comprising a shell contact and a center contact by the holder is from one another, said bulb-holder havwhich the lamp is connected in circuit, a bulb-' holder of larger diameter than the shell con- I OE tracted at one end to a diameter less than that of the shell, and a single filling of vitreous insulating material securing the contacts and bulb-holder together but insulating them one from another.

4%. Abase for an incandescent lamp, comprising insulated contacts, and a'cylindrical bulb-holder partially closed at one end by a contracted portion integral with the cylindrical portion thereof and having said end secured to this contacts- 5. A base for an incandescent lamp, comprising a shell contact and a center contact insulated from each other, and a cylindrical bulbholder of larger diameter than the shell partially closed at. one end by a contracted por tion integral with the cylindrical portion thereof and having said contracted portion secured to the contacts.

6. in a base for an incandescent lamp, in

combination with a shell and center contact, a-

to a diameter .less thanthe shell and secured to but insulated from the shell.

8. A base for an incandescent lamp, comprising insulated contacts, and a cylindrical bulb-holder partially closed at one end by a contracted portion integral with the cylindrical portion thereof and having said endsecured to but insulated from the contacts.

9. A lamp-base having a shell, a contact and a bulb-holder of greater diameter than the shell secured together but insulated one from another, said bulb-holder having a contracted portion at one end integral with the main portion and provided with a flange on the contracted edge.

10. A lamp base having ashell,a contact,and a bulbholder of greater diameter than the shell, secured together but insulated one from another, said bulb-holder having one end contracted and fitting within the shell. 7

11. A lamp-base having a threaded metallic shell and a metallic center contact secured together but insulated one from another, and

a bulb-holder of greater diameter than the shell having one end contracted to a diameter less than the shell and fitting within the same.

12. A lamp-base having a metallic shell and contact secured together but insulated one from another, and a bulb-holder of greater diameter than the shell secured thereto and provided with an opening through which one of the lead-wires of the lamp is adapted to extend for-connection to the shell.

13. A lamp-base having a threaded metallic shell, a metallic center-contact secured to but insulated from the shell, and a bulb-holder of greater diameter than the shell secured thereto and having an opening therein through which one of the lead-wires of the lamp is adapted to extend for connection to the threaded shell.

In witness whereof I have hereunto set my hand this 25th day of March, 1903. a

. ALFRED SWAN.

Witnesses:

S. N. WHITEHEAD, JOHN. E. MITCHELL, Jr. 

